The invention generally relates to devices for removing, i.e. for resecting and/or ablating organic tissue by means of high-frequency current.
The invention further relates to a resectoscope for removing organic tissue by means of high-frequency current, comprising a shaft in which a device of the aforementioned type is arranged.
Such a device or resectoscope is used in high-frequency surgery for resection and ablation of organic tissue. The device can be used in particular in hysteroscopy or in urology, in order to remove fibromas, polyps and endometrial tissue, or prostatic adenomas.
A device of the type mentioned above is known from US 2004/0064139 A1 which comprises a loop carrier, an electrically conductive loop that can be acted upon by high-frequency current, and a connection element in the form of two rectilinear strands between the loop carrier and the loop. The loop extends either in a plane transverse to a longitudinal axis of the loop carrier or in a plane that contains the longitudinal axis of the loop carrier.
In order to remove organic tissue by means of the device received in the resectoscope, said device is moved by the physician along the longitudinal direction of the loop carrier. The loop that can be acted upon by high-frequency voltage thus separates the tissue to be removed in a pulling cut. At the same time, the surface of the cut is obliterated by means of the loop, in order to stanch any bleeding. The detached pieces of tissue have to be removed from the operating site in a further step.
All the embodiments of the arrangement of loop carrier, connection element and loop that are described in the aforementioned document US 2004/0064139 A1 have the disadvantage that they are only suitable for cutting tissue by means of a pulling cut, in which the loop is thus moved in the longitudinal direction of the loop carrier.
A further device of the type mentioned at the outset is known from WO 2006/048199 A1 and comprises a loop carrier in the form of a hollow tube, a loop arranged at the distal end of the loop carrier, and a connection element designed as double helix between the loop and the loop carrier. The loop has a semicircular shape and is inclined slightly towards a longitudinal axis of the loop carrier and can be acted upon by high-frequency voltage. This device cuts tissue by means of the loop and the double helix being moved in rotation about the longitudinal axis of the hollow tube. The co-rotating double helix is also intended to serve for transporting detached organic tissue in the proximal direction, and the tissue can additionally be suctioned in the proximal direction when introduced into the tube.
Depending on the topology of the tissue that is to be cut, the semicircular loop lies more or less in a line on the tissue at the start of the cut, it also being possible for individual sections of the loop to touch the tissue while others do not. This is the case when the tissue to be cut has convex and concave areas. In other words, there is no defined point on the loop at which the cut begins. The fact that the loop bears in a line at least in some areas on the tissue to be cut means that the cutting action of the known device is also not optimal. The same also applies to the device known from US 2004/0064139 A1, in which the loop, because of its symmetry, does not permit a defined start to the cut.